(EW.com) -- Part of the great power of movies is that they can take us perilously close to the life of someone we might otherwise feel perilously far from.

The title character of "Precious: Based on the novel Push by Sapphire" is a hushed, damaged, morbidly obese 16-year-old African-American girl from the lower depths of Harlem. It's 1987, and Claireece Precious Jones is poor and ignorant, a depressed, withdrawn shell of a human being, with a face so inexpressive it might be a visor clamped down over her features.

Gabourey Sidibe, the startling newcomer who plays Precious, is actually softly pretty, with catlike eyes that narrow into a tensely focused glare. Precious speaks to us in voice-over (we hear her flowery notions of running off with a math teacher to suburban Westchester), and the film keeps cutting to her fantasies, which are spangly, TV-addict daydreams in which she whirls around in silk and feather boas, adored by the world.

Outside those fantasies, Precious can't imagine a life. She rarely talks, never smiles, and hardly even frowns; she looks like it would take too much effort. Sidibe plays her with barely visible tremors of feeling that cue us to what this arrested girl is holding back. She's an almost totally passive protagonist, cut off from everyone, including us.

Yet there's nothing passive about the way the director, Lee Daniels, working from a script by Geoffrey Fletcher, plunges us into the nightmare that is Precious' daily, hidden existence.

Sometimes, a movie has to take you down -- and I mean down, really far -- to lift you up. "Precious" is that kind of movie. Daniels, a former producer whose credits include "Monster's Ball," ushers us into the dingy Harlem flat where Precious lives, and there, amid the dank light and moldy yellow-flower wallpaper, we see the forces that have made her who she is.

There are stinging flashbacks of abuse (she's now pregnant, for the second time, by her drug-addict father), and we witness the Gordian knot of her relationship with her mother, Mary (Mo'Nique), who's a scalding pit of bitterness. Their twisted and tormented co-dependence is harrowing to behold, but it's also as indelible as something out of Tennessee Williams.

In her first dramatic role, the comedian Mo'Nique acts with such force that she burns a hole in the screen. Her Mary is raging and defeated, a woman who treats Precious as a slave -- and I don't use the word lightly, since part of the film's power is its perception that these two are living out patterns of cruelty that go back for generations. Their agony has roots.

What's terrifying about the abuse here is how casually it's accepted as a fact of life, by both perpetrator and victim. Mary hates her daughter because she thinks that Precious has "stolen" her man. Yet she also exploits her as a welfare ticket. How to escape this hell?

One night, the two get a visit from a school administrator, who wants to enroll Precious in a special program for problem students. Quietly, almost instinctively, Precious signs up. The program becomes her pathway out of the madness and into a real life. And if that sounds like a facile feel-good scenario, the way that Daniels stages it, sticking to the merciless outline of Sapphire's novel, it's more like a slow walk of redemption marked by tiny roadside bombs that keep going off.

Precious comes to the attention of a welfare counselor, played by Mariah Carey with an authentically deglammed compassion, and once she's in the class, she starts to wake up. These episodes aren't the usual inspirational claptrap; they're about troubled girls striving, and often failing, to turn themselves around. The more Precious tries to get away from her mother, the more she's pulled back, and the final scene of revelation between them will leave you tearful, shaken, dazed with pity and terror.

Precious captures how a lost girl rouses herself from the dead, and Daniels shows unflinching courage as a filmmaker by going this deep into the pathologies that may still linger in the closets of some impoverished inner-city lives.

"Precious" is a film that makes you think, "There but for the grace of God go I." It's a potent and moving experience, because by the end you feel you've witnessed nothing less than the birth of a soul.